Brad Bishop | d5ae7d9 | 2018-06-14 09:52:03 -0700 | [diff] [blame] | 1 | Upstream-Status: Backport |
| 2 | |
| 3 | https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg01012.html |
| 4 | |
| 5 | From dc21a9d2951f0a2a7e63633e2b5c68c54e4edc4b Mon Sep 17 00:00:00 2001 |
| 6 | From: Jeremy Puhlman <jpuhlman@mvista.com> |
| 7 | Date: Thu, 14 Jun 2018 01:28:49 +0000 |
| 8 | Subject: [PATCH] CVE-2018-11806 QEMU: slirp: heap buffer overflow |
| 9 | |
| 10 | Subject: [Qemu-devel] [PATCH 1/2] slirp: correct size computation while concatenating mbuf |
| 11 | Date: Tue, 5 Jun 2018 23:38:35 +0530 |
| 12 | From: Prasad J Pandit <address@hidden> |
| 13 | |
| 14 | While reassembling incoming fragmented datagrams, 'm_cat' routine |
| 15 | extends the 'mbuf' buffer, if it has insufficient room. It computes |
| 16 | a wrong buffer size, which leads to overwriting adjacent heap buffer |
| 17 | area. Correct this size computation in m_cat. |
| 18 | |
| 19 | Reported-by: ZDI Disclosures <address@hidden> |
| 20 | Signed-off-by: Prasad J Pandit <address@hidden> |
| 21 | --- |
| 22 | slirp/mbuf.c | 8 ++++---- |
| 23 | 1 file changed, 4 insertions(+), 4 deletions(-) |
| 24 | |
| 25 | Signed-off-by: Jeremy Puhlman <jpuhlman@mvista.com> |
| 26 | --- |
| 27 | slirp/mbuf.c | 8 ++++---- |
| 28 | 1 file changed, 4 insertions(+), 4 deletions(-) |
| 29 | |
| 30 | diff --git a/slirp/mbuf.c b/slirp/mbuf.c |
| 31 | index 5ff2455..7fb4501 100644 |
| 32 | --- a/slirp/mbuf.c |
| 33 | +++ b/slirp/mbuf.c |
| 34 | @@ -138,7 +138,7 @@ m_cat(struct mbuf *m, struct mbuf *n) |
| 35 | * If there's no room, realloc |
| 36 | */ |
| 37 | if (M_FREEROOM(m) < n->m_len) |
| 38 | - m_inc(m,m->m_size+MINCSIZE); |
| 39 | + m_inc(m, m->m_len + n->m_len); |
| 40 | |
| 41 | memcpy(m->m_data+m->m_len, n->m_data, n->m_len); |
| 42 | m->m_len += n->m_len; |
| 43 | @@ -158,12 +158,12 @@ m_inc(struct mbuf *m, int size) |
| 44 | |
| 45 | if (m->m_flags & M_EXT) { |
| 46 | datasize = m->m_data - m->m_ext; |
| 47 | - m->m_ext = g_realloc(m->m_ext, size); |
| 48 | + m->m_ext = g_realloc(m->m_ext, size + datasize); |
| 49 | m->m_data = m->m_ext + datasize; |
| 50 | } else { |
| 51 | char *dat; |
| 52 | datasize = m->m_data - m->m_dat; |
| 53 | - dat = g_malloc(size); |
| 54 | + dat = g_malloc(size + datasize); |
| 55 | memcpy(dat, m->m_dat, m->m_size); |
| 56 | |
| 57 | m->m_ext = dat; |
| 58 | @@ -171,7 +171,7 @@ m_inc(struct mbuf *m, int size) |
| 59 | m->m_flags |= M_EXT; |
| 60 | } |
| 61 | |
| 62 | - m->m_size = size; |
| 63 | + m->m_size = size + datasize; |
| 64 | |
| 65 | } |
| 66 | |
| 67 | -- |
| 68 | 2.13.3 |
| 69 | |